This invention relates to a nuclear reactor installation having a containment wall which on one side forms a reactor room in which a reactor pressure vessel is positioned, and on its other side forming a fuel element handling pit. A fuel element transfer tube extends through the wall and is proportioned for the endwise transfer of fuel elements in either direction between the room and pit. After endwise travel transversely through the wall via the tube, the elements must be erected or turned to vertical positions for handling by the reactor refueling machine and the fuel element handling equipment in the pit.
For effecting the transfer of fuel elements through the tube, the U.S. Crate Pat. No. 3,637,096, dated Jan. 25, 1972, discloses the transfer tube in a conventional horizontal position. An elongated carriage on which a fuel element carrier is pivoted runs on horizontal tracks extending through the tube and to carrier erecting locations in the room and pit, at which locations curved guideways with which the pivoted carrier is engaged, turn upwardly and downwardly, respectively, so that with horizontal travel of the carriage the carrier, pivoting with respect to the carriage, is erected. To apply the necessary travel force to the carriage, the latter is provided with a submersible electric motor powering wheels on which the carrier runs on the horizontal tracks, the motor being powered via an electric cable handled via a power supply and retrieval reel mounted above the pit. In the event of an electric power failure, this reel may be used, being presumably powered, to withdraw the carriage and carrier to the pit.
Such a power failure is a possibility because a submersible electric motor is required and this motor must connect with the carriage wheels by a drive arrangement, it being understood that both the reactor room and pit and transfer tube are water-flooded during fuel element transfer operations. The electric cable itself is for the same reason apt to fail, and if protected by armor, its flexibility is reduced.